Wednesday, June 16, 2021

Settling with Power / Vortex Ring State: Bell UH-1H, N398M; accident occurred June 15, 2021 in Townsend, Broadwater County, Montana





Aviation Accident Final Report - National Transportation Safety Board

The National Transportation Safety Board did not travel to the scene of this accident. 

Additional Participating Entity: 
Federal Aviation Administration / Flight Standards District Office; Helena, Montana

Investigation Docket - National Transportation Safety Board: https://data.ntsb.gov/Docket

USDA Forest Service Federal Excess Personal Property Program 


Location: Townsend, Montana
Accident Number: WPR21LA236
Date and Time: June 15, 2021, 17:00 Local 
Registration: N398M
Aircraft: Bell UH-1H 
Aircraft Damage: Destroyed
Defining Event: Settling with power/vortex ring state 
Injuries: 5 None
Flight Conducted Under: Public aircraft 

Analysis

The pilot reported that, during the approach to the landing area, he made visual contact with the airport manager who cleared him to land on the west end of the pull-off tarmac. The pilot noted evidence of wind from the blowing willows from south-west. He initiated a left downwind approach, and upon turning from base to final at 500 ft above ground level, the helicopter started to settle with power and the pilot experienced a nearly direct tailwind. Due to the approach speed and proximity to the ground, the pilot was unable to fly out, so he leveled the helicopter and committed to landing. The helicopter touched down hard, spun right about 120° and rolled left upside down. The helicopter was destroyed by impact forces and postaccident fire. The pilot reported that there were no mechanical malfunctions or failures with the helicopter that would have precluded normal operation.

Probable Cause and Findings

The National Transportation Safety Board determines the probable cause(s) of this accident to be:
The pilot’s failure to maintain helicopter control after an encounter with settling with power during approach at an altitude that was too low for recovery, which resulted in a hard landing.

Findings

Personnel issues Decision making/judgment - Pilot
Personnel issues Aircraft control - Pilot
Aircraft Descent rate - Attain/maintain not possible

Factual Information

History of Flight

Landing-flare/touchdown Settling with power/vortex ring state (Defining event)

Pilot Information

Certificate: Commercial 
Age: 57, Male
Airplane Rating(s): None
Seat Occupied: Left
Other Aircraft Rating(s): Helicopter
Restraint Used: 4-point
Instrument Rating(s): Helicopter
Second Pilot Present:
Instructor Rating(s): None 
Toxicology Performed:
Medical Certification: Class 2 With waivers/limitations 
Last FAA Medical Exam: April 21, 2021
Occupational Pilot: Yes 
Last Flight Review or Equivalent: April 18, 2021
Flight Time: 8079 hours (Total, all aircraft), 2681 hours (Total, this make and model), 6429 hours (Pilot In Command, all aircraft), 99 hours (Last 90 days, all aircraft), 34 hours (Last 30 days, all aircraft), 6 hours (Last 24 hours, all aircraft)

Passenger Information

Certificate:
Age:
Airplane Rating(s): 
Seat Occupied: Right
Other Aircraft Rating(s):
Restraint Used: 4-point
Instrument Rating(s): 
Second Pilot Present:
Instructor Rating(s): 
Toxicology Performed:
Medical Certification: 
Last FAA Medical Exam:
Occupational Pilot: No 
Last Flight Review or Equivalent:
Flight Time:

Passenger Information

Certificate: 
Age:
Airplane Rating(s): 
Seat Occupied: Center
Other Aircraft Rating(s): 
Restraint Used: 4-point
Instrument Rating(s): 
Second Pilot Present:
Instructor Rating(s): 
Toxicology Performed:
Medical Certification: 
Last FAA Medical Exam:
Occupational Pilot: No 
Last Flight Review or Equivalent:
Flight Time:

Passenger Information

Certificate: 
Age:
Airplane Rating(s): 
Seat Occupied: Right
Other Aircraft Rating(s):
Restraint Used: 4-point
Instrument Rating(s):
Second Pilot Present:
Instructor Rating(s): 
Toxicology Performed:
Medical Certification:
Last FAA Medical Exam:
Occupational Pilot: No 
Last Flight Review or Equivalent:
Flight Time:

Passenger Information

Certificate: 
Age:
Airplane Rating(s): 
Seat Occupied: Left
Other Aircraft Rating(s):
Restraint Used: 4-point
Instrument Rating(s):
Second Pilot Present:
Instructor Rating(s):
Toxicology Performed:
Medical Certification: 
Last FAA Medical Exam:
Occupational Pilot: No 
Last Flight Review or Equivalent:
Flight Time:

Aircraft and Owner/Operator Information

Aircraft Make: Bell 
Registration: N398M
Model/Series: UH-1H 
Aircraft Category: Helicopter
Year of Manufacture: 1965
Amateur Built:
Airworthiness Certificate: None
Serial Number: 65-09984
Landing Gear Type: High skid
Seats: 8
Date/Type of Last Inspection: December 7, 2020 Annual
Certified Max Gross Wt.: 9500 lbs
Time Since Last Inspection:
Engines: 1 Turbo shaft
Airframe Total Time: 14620 Hrs at time of accident
Engine Manufacturer: LYCOMING
ELT: C91 installed, not activated 
Engine Model/Series: T53-L-703
Registered Owner:
Rated Power: 1800 Horsepower
Operator: 
Operating Certificate(s) Held: None

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual (VMC) 
Condition of Light: Day
Observation Facility, Elevation: KHLN,3868 ft msl
Distance from Accident Site: 33 Nautical Miles
Observation Time: 16:53 Local
Direction from Accident Site: 302°
Lowest Cloud Condition: Clear
Visibility: 10 miles
Lowest Ceiling: None
Visibility (RVR):
Wind Speed/Gusts: 10 knots / 
Turbulence Type Forecast/Actual:  /
Wind Direction: 310°
Turbulence Severity Forecast/Actual:  /
Altimeter Setting: 29.84 inches Hg
Temperature/Dew Point: 32°C / 9°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: Helena, MT 
Type of Flight Plan Filed: Company VFR
Destination: TOWNSEND HELISPOT, MT
Type of Clearance: None
Departure Time: 16:35 Local
Type of Airspace: Class G

Wreckage and Impact Information

Crew Injuries: 1 None
Aircraft Damage: Destroyed
Passenger Injuries: 4 None
Aircraft Fire: On-ground
Ground Injuries: 
Aircraft Explosion: None
Total Injuries: 5 None 
Latitude, Longitude: 46.3245,-111.291

1 comment:

  1. This US Forest Service chopper is mostly used as a firefighting bird. It is going to be a bad fire season this summer in the drought stricken west and it's only getting off to a start with hundreds of large fires already in progress. Sadly that means there is greater risk of crashes and a loss of life of our heroic aerial firefighters. Prayers to them all.

    ReplyDelete